AUSTIN — The leader of the Zetas drug cartel's favorite band played his niece's wedding in Dallas, members of his family flashed him hand signs when their horse won a Texas race, and quarter horses were transferred into his brother's name just before they ran races that the gang fixed, an FBI agent has testified here.

Prosecutors have largely wrapped up their case against five men accused of laundering money for the Zetas.

On Wednesday, FBI agent Scott Lawson, one of two federal agents who oversaw the investigation into what prosecutors allege was a scheme to launder drug money through the Texas quarter horse industry, took the witness stand.

Performing, he said, was Banda el Recodo, a popular group that Zetas founding member Jesús Enrique “El Mamito” Rejón Aguilar testified is Miguel Treviño's favorite band.

Jurors were shown a picture of José Treviño's family after one of his horses won the 2009 Dash for Cash Futurity in Grand Prairie.

In the picture, Alexandra Garcia Treviño is making hand signs for the numbers four and zero, and José Treviño's son is making hand signs for the numbers four and two.

Lawson testified they were holding up signs for Miguel Treviño, who goes by the radio call sign “El 40,” and his brother Omar, who goes by the call sign “El 42.” Both are fugitives.

In wiretap recordings played this week, jurors heard Omar Treviño ask an associate to make a hand sign to him from the winner's circle.

But defense attorney Christie Williams pointed out that the winning horse, Tempting Dash, had won four races with no losses and set two track records.

During cross examination by Guy Womack, Garcia's attorney, Lawson acknowledged that he could get a $25,000 bonus for his work on the case. That opened the door for prosecutor Douglas Gardner to ask Lawson why he pursued the money-laundering investigation.

“This case is important to me,” he said. “I live on the border, and in my time of living on the border I know what the Zetas cartel is capable of and how they entrench themselves in the U.S. So this is a way to show them the United States is not a place for them to come set up roots.”